Image forming apparatuses are devices for forming images on printing media according to input signals, and examples thereof include printers, copiers, facsimiles, and all-in-one devices implemented by a combination thereof.
One type of image forming apparatus, an electrophotographic image forming apparatus, includes a main body, a plurality of developing units which develop a visible image from an electrostatic latent image through a developer for each color in the main body, an exposure device which projects light onto photoreceptors of the plurality of developing units to form the electrostatic latent image on a photoreceptor of each developing unit, a transfer device which transfers the visible image developed on the photoreceptors to a printing medium, and a fixing device which fixes the developer onto the printing medium.
The transfer device includes a transfer member which receives the developer from the plurality of developing units and transfers the developer onto the printing medium, and a sensing unit which inspects the developer on the transfer member is disposed under one side of the transfer member.